As of September 2013, Facebook accounted for more than 10% of social site traffic to the publishers studied -- driving more traffic than the other 7 social media platforms combined.

Facebook, Pinterest, and Twitter are the dominant traffic-referring platforms; each has grown more than 50% in share of overall visits in the past year. Pinterest grew 66.52%, Facebook 58.81%, and Twitter by 54.12%.

Interestingly, Pinterest, having grown by 66.52% to 3.68%, now drives more traffic than Twitter, StumbleUpon, Reddit, YouTube, LinkedIn and Google+ combined.